1. Field of the Invention
The present invention relates to a disc changer, in which a desired record medium is selected from record media such as magnet-optical disc, optical discs or the like that are received in a magazine or the like, and a record or reproduction operation for the selected record medium is carried out.
2. Description of the Related Art
There has conventionally been know a disc changer, in which a desired record medium is selected from record media such as magnet-optical disc, optical discs or the like and a record or reproduction operation for the selected record medium is carried out. The disc changer has a receiving unit for receiving a plurality of discs, a playback unit for carrying out a record or reproduction operation for the disc, and a transfer unit for transferring the disc from the receiving unit to the playback unit. The receiving unit receives discs in a stacked state. The transfer unit moves vertically to a position of the prescribed disc relative to the base unit to transfer the disc from the receiving unit to the playback unit.
FIG. 7 illustrates a changer that is provided with a transfer unit 71 and a playback unit 72, which are formed independently. In the changer, the receiving unit 73 and the playback unit 72 are placed on the base unit 74. The transfer unit 71 locates above the playback unit so as to move vertically.
The transfer operation of the disc from the receiving unit 73 to the playback unit 72 is carried out in the following manner. First, the transfer unit 71 moves linearly to a position of the prescribed disc. The prescribed disc is pulled from the receiving unit 73 into the transfer unit 71 and the transfer unit 71 moves down to place the disc on the playback unit 72.
FIG. 8 illustrates an example of the changer in which the playback unit is integrally formed with the transfer unit. In such an example, the transfer unit and the playback unit, which are integrally formed with each other, move up to a position of the prescribed disc, pulls the prescribed disc from the receiving unit 75 and to transfer it to the playback unit 76. Then, a playback operation in the playback unit 76 starts.
However, in any one of the conventional changers described above, a selection operation in which the transfer unit moves vertically to a position of the prescribed disc is carried out so that the linearly vertical movement is made, while maintaining a parallel posture of the transfer unit with the base unit. With respect to an elevation mechanism for moving vertically the transfer unit, guide shafts are provided on the base unit so as to project upward and the transfer unit is guided by means of these guide shafts so as to be movable linearly. The vertical movement of the transfer unit is caused by a rack and pinion mechanism. Such an elevation mechanism in which the linearly vertical movement is made, while maintaining the parallel posture of the transfer unit with the base unit, requires enlarged structural elements and leads to the complicated structure.
The ejection operation for discharging the disc from the disc changer is carried out for each of the discs received in the receiving unit. It is therefore necessary to provide an ejection mechanism for each of the leading to the complicated structure.
The selection operation and the ejection operation are carried out by the separate driving power sources. Provision of the plurality of driving power sources makes the entire structure complicated.
An object of the present invention is therefore to provide a disc changer, which has a simple structure by which an ejection operation and a selection operation can be carried out.
In order to attain the aforementioned object, in the present invention, an selection operation is carried out so as to make an up and down movement not along a straight line, but along a curve for approximation to the straight line, while maintaining a parallel posture of the transfer unit with the base unit or the similar posture thereto, within a range in which the disc is pulled out of the receiving unit. More specifically, the disc changer of the present invention comprises:
a receiving unit for receiving a plurality of discs;
a base unit;
a playback unit; and
a transfer unit for transferring one of said plurality of discs to said playback unit, said transfer unit being movable in a perpendicular direction to said base unit,
wherein:
said playback unit has on its opposite ends swing support axes, said playback unit being swingable around said swing support axes relative to said base unit and said transfer unit, respectively, said playback unit having a gear;
said base unit has a base unit-gear segment portion and said transfer unit has a transfer unit-gear segment portion, said gear being held between said base unit-gear segment portion and said transfer unit-gear segment portion so as to engage with these gear segment portions.
According to the feature of the present invention, the one end of the transfer unit is supported by engagement of the transfer unit-gear segment portion with the gear provided on the playback unit and the other end of the transfer unit is supported by one of the swing support axes of the playback unit. The swing of the playback unit relative to the base unit causes the transfer unit to move substantially linearly, while maintaining substantially the parallel posture of the transfer unit with the base unit. The selection operation can therefore be carried out by a simple structure.
In the other disc changer of the present invention, the receiving unit for receiving the plurality of discs moves horizontally relative to the base unit to discharge simultaneously all the discs. The structure of the disc changer for making the ejection operation can be simplified. The ejection operation and the selection operation are carried out by the single driving power source in order to obtain the disc changer having the simpler structure. More specifically, the disc changer of the present invention comprises:
a receiving unit for receiving a plurality of discs;
a base unit; and
a transfer unit being movable in a perpendicular direction to said receiving unit,
wherein:
an ejection operation in which said receiving unit slides in a horizontal direction relative to said base unit and a selection operation in which said transfer unit moves to a prescribed position of one of said plurality of discs are carried out by a single driving power source. The relative movement of the transfer unit may include the movement of the transfer unit relative to the receiving unit and the movement of the receiving unit relative to the transfer unit.
According to the features of the present invention, the single driving power source for the ejection operation and the selection operation makes the structure of the disc changer simple. It is also possible to manufacture the disc changer in a smaller size.
In the first disc changer of the present invention, an ejection operation in which said receiving unit slides in a horizontal direction relative to said base unit and a selection operation in which said transfer unit moves to a prescribed position of one of said plurality of discs may be carried out by a single driving power source.
According to such a feature, the selection operation can be conducted by a simple structure. The single driving power source for the ejection operation and the selection operation makes the structure of the disc changer simple.
The first disc changer of the present invention may further comprise a cam device, which swings said playback unit relative to said base unit and slides said receiving unit in the horizontal direction relative to said base unit.
According to such a feature, the cam device causes the playback unit to swing relative to the base unit and the transfer unit moves perpendicularly to the base unit. The receiving unit slides horizontally relative to the base unit utilizing an overstroke of the cam device. Accordingly, the selection operation and the ejection operation can be carried out by a simpler structure.
In the first disc changer of the present invention, there may be adopted a structure that said playback unit has a wedge portion that is capable of projecting, said cam device causing said wedge portion to project to engage with said base unit so as to restrict a swing motion of said playback unit.
According to such a structure, it is possible to prevent the playback unit from swinging during transportation of the disc changer by projecting the wedge portion from the playback unit.
In the first disc changer of the present invention, there may be adopted a structure that there is provided a pawl for maintaining a prescribed swing angle of said playback unit relative to said base unit so that an assembly operation can be carried out, while keeping said transfer unit substantially in parallel with said base unit.
According to such a structure, when the base unit and the playback unit are assembled during an assembly operation, the playback unit is placed on the pawl so as to maintain a prescribed swing angle of the playback unit relative to the base unit. The gear provided on the playback unit engages with the base unit-gear segment portion at a prescribed position. When the playback unit is combined with the transfer unit, the transfer unit-gear segment portion is placed on a prescribed position of the gear of the playback unit. When the pawl is removed, the playback unit swings-so that the gear of the playback unit engages with the transfer unit-gear segment portion and the base unit-gear segment portion. As a result, the assembly operation can be carried out, while maintaining substantially a parallel posture of the transfer unit relative to the base unit.